1. Field of the Invention The present invention relates to a method of manufacturing an antenna for a radio frequency identification (RFID) tag.
2. Description of the Related Art
An RFID tag typically includes a single antenna or an antenna formed by a single closed loop, and at least one integrated circuit chip electrically connected to the antenna. Information is stored in the integrated circuit chip through the antenna, and information that is stored in the integrated circuit chip is updated or transmitted by an RFID reader/programmer through the antenna.
Such an RFID tag may be applied to various fields of logistics management system, electronic cash, credit card, or the like. The RFID tag is inputted with previously set data through a contact input system or contactless input system. More particularly, an input of a terminal comes into contact with a contact substrate formed on an electronic radio frequency identification device to implement operation of interest, or the RFID tag is recorded with initial information by a writer for RFID tag. In the practical use after the initial information is recorded in the RFID tag, the data is wirelessly communicated between the RFID tag and the terminal.
Examples of a conventional electronic radio frequency identification apparatus are shown in FIGS. 1 through 4, in which FIGS. 1 and 3 are plan views of a conventional RFID tag, FIG. 2 is a cross-sectional view taken along a line II-II in FIG. 1, and FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 3.
Referring to FIGS. 1 through 4, RFID tags 10 and 20 include an RFID integrated circuit chip 12 and an antenna 11.
The RFID integrated circuit chip 12 is electrically connected to the antenna 11, so that the chip is actuated by energy produced due to an electromagnetic field induced according to Faraday's law to store, retrieve and update information. The RFID integrated circuit chip 12 is electrically connected to a terminal of the antenna 11 through an anisotropic conductive film (ACF) 13.
The antenna 11 is formed in the shape of a coil along a border of the RFID tag 10, 20 to form a closed loop. The antenna 11 is configured to have a certain resonance frequency, so that the antenna 11 receives new information through radio communication with a reader (not shown) to store the information in the integrated circuit chip 12 or transmit the information from the chip 12 to the reader.
As shown in FIGS. 1 and 2, both ends 11a and 11b of the antenna 11 may be connected to each other through a crimping connection 14 and a metal (e.g., aluminum) foil 15 so as to form the antenna 11 in the shape of a closed loop.
As shown in FIGS. 3 and 4, both ends 11a, 11b of the antenna 11 may be connected to a terminal 25 that is, for example, made of silver, through a portion insulated by a solder resist 27.
The antenna 11 for the RFID tag 10, 20 configured as described above is generally manufactured through etching. More particularly, an insulating film is applied with a photoresist, and is subjected to an exposure process by use of a photomask. Unwanted portions are exposed and removed from the insulating film through etching (e.g., chemical etching) to form the antenna 11 from a metallic layer that is deposited or otherwise disposed on the insulating film.
Alternatively, ink is printed on an insulating film in a desired pattern corresponding to an antenna shape by use of a screen mask. The pattern formed with the ink is cured, and the other portion is removed by etching, thereby forming the antenna.
The above methods have a drawback in that an amount of the material to be removed is more than a material to be used for the antenna. Also, the foregoing methods involve time consuming and complicated processes. Moreover, since the photomask and screen mask are expensively formed, manufacturing costs of masked and etched antennas for RFID tags are increased. As such, a new method of manufacturing an antenna for an RFID tag is highly demanded to solve the above drawbacks.